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DESCRIPTION
J u l y 8 , 2 01 4. T O :. C e n t r ali a Ci ty Co u n ci l M e mb ers. FR O M:. S co tt B o e tt c her, S t aff , C R B F A ( 3 60/ 4 80 - 6600 , sco tt b @ sb gh - p a r t n er s.co m ). SUBJE C T:. - PowerPoint PPT PresentationTRANSCRIPT
July 8, 2014TO: Centralia City Council
MembersFROM:
Scott Boettcher, Staff, CRBFA (360/480-6600, [email protected])
SUBJECT: Brief Update of Flood Hazard Reduction Activities in the Chehalis Basin
Outreach/Education Presentation: https://www.ezview.wa.gov/site/alias1492/34490/outreacheducation.aspx.May 2014 Public Meeting: https://www.ezview.wa.gov/site/alias1492/34798/meetings_2013-15.aspx.Local Project Construction Photos: https://www.ezview.wa.gov/site/alias1492/35040/Default.aspx.
1. Local Projects Completed (or by flood season): Adna Levee. Bucoda Water Supply Levee. Montesano WWTP Levee. Chehalis Tribe Sickman-Ford Overflow Bridge. 5 Livestock and Equipment Pads. 2 Livestock Evacuation Routes. 10 Additional Livestock/Equipment Pads. 2 Capacity Expansions For Existing Pads. 1 Evacuation Route. Montesano Sheet Pile Wall. Airport Levee Phase IA. Pe Ell WWTP Protection Levee. Map = http://goo.gl/maps/Vq8YY.
2. Local Projects Proposed for Further Review/Evaluation/Costing**: Kirkland Road Flooding Study. SR6 Bypass and Road Raise. Dillenbaugh Creek Realignment. Chehalis Main Street Regrade. Salzer Creek. Preliminary designs/costs (Summer
2014). Map = http://goo.gl/maps/QqnV5.
3. Aquatic Species Enhancement**: Salmon populations are 15-25% of historic levels. Evaluating habitat enhancement options,
benefits, costs (barrier removal, riparian enhancement, water quantity/quality, etc.).
Preliminary plan (Summer 2014). $63M - $134M.
4. Upper Basin Retention Structure**: Evaluating options, benefits, costs, impacts:
o Flood Retention only ($265M - $421M).o Multipurpose (fish, water, hydro) ($369M -
$708M). Preliminary design (Summer 2014).
5. I-5 Protection**: Evaluating protecting I-5 w/ walls, levees, berms. Dropped raising or relocating I-5. Preliminary design (Summer 2014). $80M - $100M.
6. Flood Proofing**: Evaluating options, benefits, costs of flood
proofing residential, commercial, agricultural structures in floodplain.
Compare costs w/ and w/out Dam (Summer 2014).
$92M ($57M, $21M, $14M).7. Basin Relationships/Partnerships:
Very strong.8. Looking Ahead:
Sept. 2014 – Technical, policy, public workshops. Nov. 2014 – Recommendations to Gov./Leg. $500M - $1B.
Salmon Runs
0
20000
40000
Winter-run Steelhead TR
60000
80000
100000
1970 1973 1976 1979 1982 1985 1988 1991 1994Year
1997 2000 2003 2006 2009 2012
Num
ber o
f Ret
urns
120000
Coho ESC
Coho TRFall-run Chinook ESC
Fall-run Chinook TR Spring-run Chinook ESC
Spring-run Chinook TRWinter-run Steelhead ESC
(Pg. 2)
11
Other Fish and Aquatic Species
Olympic Mudminnow
Redside Shiner
Northern Pikeminnow
Longnose Dace
Largescale Sucker
Sculpin (6 species)
Oregon Spotted Frog
Andrew O’Connor
Western Toad
14
(Pg. 3)
Flood Retention Only Reservoir
• Dam Height = 227’• Spillway Crest Elev. = 628• Dam Crest Elev. = 654• Area = 860 Acres• River Inundation Length = 6.8 mi• Maximum Storage = 65K
acre/feet
27
(Pg. 4)
Multi-purpose Reservoir Overview
• Dam Height = 287’• Spillway Crest Elev. = 687• Dam Crest Elev. = 714• Area = 1,307 Ac• River Inundation Length = 7.5 mi• Maximum Storage = 130K
acre/feet
29
(Pg. 5)
Protect I-5 with walls and levees
Project Cost: $ 80 – 100 Million
(Pg. 6)
(Pg. 7)
Floodproofing - Structures Affected
55
Summary of Structures At Risk of Flooding in Chehalis River Floodplain
Number of Structures Baseline With Dam and Airport Levee
Dec 07 500-Year 100-Year 20-Year 10-Year Dec 07 500-Year 100-Year
Flooded 2040 3645 1384 372 175 753 2031 821
>1.0 feet 1368 2743 829 167 83 432 1306 459
>2.0 feet 820 1926 489 76 28 241 762 241
>3.0 feet 470 1159 293 22 7 139 471 117
>4.0 feet 263 657 155 6 2 65 300 54
>5.0 feet 159 385 76 1 0 28 158 25
Assessed Value of Improvements
Inundated ($Million)
$238 $411 $137 $30 $13 $64 $206 $73
Cost to Floodproof all Inundated Structures
($Million)
$146 $273 $92 $20 $9 $46 $149 $50
Residential ($ Mil) $107 $205 $57 $10 $4 $28 $101 $28Commercial ($ Mil) $26 $44 $21 $6 $3 $11 $26 $12Agricultural ($ Mil) $13 $24 $14 $4 $2 $7 $22 $10
12
1. Basin-Wide Relationships
(Pg. 8)